Hospitalizations associated with influenza and respiratory syncytial virus among patients attending a network of private hospitals in South Africa, 2007–2012

Abstract

BackgroundInfluenza and respiratory syncytial virus (RSV) infection are common causes of lower respiratory tract illness. Data on their burden in low and middle-income settings and from Africa are scarce. We aimed to estimate age-specific rates of hospitalization attributable to influenza and RSV among patients attending private hospitals in South Africa during 2007–2012.MethodsWe estimated annual age-specific rates of influenza- and RSV-associated hospitalization (that is respiratory hospitalizations likely due to influenza or RSV infection) by applying regression models to monthly administrative hospitalization data from a national private hospital group, using influenza and RSV surveillance data as covariates.ResultsEstimated mean hospitalization rates associated with seasonal influenza were 75 (95% confidence interval (CI), 41–108) and 3 (95% CI, 2–5) per 100,000 person-years for all-respiratory and all-circulatory causes, respectively. Children <1 year and adults ≥75 years were the most affected, with influenza-associated all-respiratory hospitalization rates estimated at 255 (95% CI, 143–358) and 380 (95% CI, 227–506) per 100,000 person-years, respectively. Excess all-circulatory hospitalizations associated with seasonal influenza were only observed in adults ≥65 years. Annual hospitalization rates associated with RSV averaged an estimate of 223 (95% CI, 128–317) per 100,000 person-years for all-respiratory causes. Among children <1 year, RSV-associated all-respiratory hospitalization rate of 7,601 (95% CI, 4,312-10,817) per 100,000 person-years was estimated.ConclusionsInfluenza and RSV substantially contributed to hospitalizations over the study period.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-014-0694-x) contains supplementary material, which is available to authorized users.

Incidence of medically attended influenza among residents of Shai-Osudoku and Ningo-Prampram Districts, Ghana, May 2013 – April 2015

“…This is consistent with Nair et al’s finding that the global burden of illness attributable to influenza in young children is substantial [12]. A study in South Africa found that children aged <1 year and adults aged >75 years had the highest rates of influenza-associated respiratory hospitalization estimated at 255 per 100,000 person-years and 380 per 100,000 person-years, respectively [13]. Similarly, Emukule et al estimated the annual incidence of hospitalized influenza-associated SARI among children aged <5 years in Kenya to be between 180 and 390 cases per 100,000 person-years [14].…”

The national burden of influenza‐associated severe acute respiratory illness hospitalization in Zambia, 2011‐2014

“…Specifically in a study conducted in South Africa, influenza virus was detected in 5.8% of patients hospitalized with respiratory illnesses that did not meet the SARI case definition 25. Last, ecological studies have suggested that influenza virus is responsible for hospitalizations and deaths also among patients presenting with circulatory illnesses or even syndromes different than respiratory and circulatory 23, 26. In addition, individuals that may have developed influenza‐associated severe respiratory illness, but did not seek care, would have been missed in our study; hence, our estimates should be considered minimum estimates.…”

The national burden of influenza‐associated severe acute respiratory illness hospitalization in Rwanda, 2012‐2014

“…Specifically in a study conducted in South Africa, influenza virus was detected in 5.8% of patients hospitalized with respiratory illnesses that did not meet the SARI case definition 24. In addition, ecological studies have suggested that influenza virus is responsible for hospitalizations and deaths also among patients presenting with circulatory illnesses or even non‐respiratory and non‐circulatory syndromes 5, 6, 19. Third, we did not collect data on the total number of medical hospitalizations, hindering our ability to estimate the proportional contribution of SARI‐associated admissions among any medical admission.…”